Technical Field
The present invention relates to a production method for concentrated products using a freeze-concentration method.
Description of the Prior Art
The freeze-concentration method is provided for preventing a liquid to be treated (as derived from the fluid to be treated) from being heated excessively while it is being concentrated, and can provide concentrated liquids without causing any changes in the flavor or taste due to the applied heating or warming effects (as represented by the disagreeable odors produced by the applied heating and the like).
Typically, the freeze-concentration method includes the suspension crystal deposition method (the suspension crystal concentration method) for generating an ice crystal in granular forms within the crystal deposition container and the interfacial advance freeze-concentration method for allowing an ice crystal to be grown onto the cooled surface, both of which are known to the prior art. In general, the interfacial advance freeze-concentration method is very often employed as the freeze-concentration method because it is considered that this method provides the easy solid-liquid separation such as the separation of ice (water) and concentrated liquid.
As one example of the freeze-concentration apparatus, the Patent Document 1, which was granted under the Japanese patent No. 4306018, proposes to provide the scraper-type heat-conducting freeze-concentration method and the scraper-type apparatus that implements that method. As another example of the freeze-concentration apparatus, the Patent Document 2, which was granted under the Japanese patent No. 4429665, proposes to provide the advance freeze-concentration method and the apparatus that implements that method.
Another freeze-concentration method is also proposed which can prevent the quality of the concentrated liquids, such as fruit juice, coffee, teas and the like among other foods in liquid forms, from being affected or reduced. As still another example of the freeze-concentration method, the Patent Document 3 describes that the reduction of the quality of the concentrated liquid such as the fruit juice and the like could be prevented by combining the interfacial advance freeze-concentration method with the deoxidizing process. In addition, it describes that this method can also be applied to milk.
As one example of the suspension crystal concentration method, the Patent Document 4 proposes to provide a method that includes several concentration stages and wherein the concentration can be provided efficiently by using the suspension crystal concentration method, that is, by forming a specific crystal having a predetermined size during one of the stages, transferring the thus formed specific crystal to the recrystallizing container containing a concentrated liquid with a low concentration degree during another stage and transferring the resulting specific crystal to the recrystallizing container containing a concentrated liquid with a lower concentration degree during still another stage.